Alkylresorcinols

Alkylresorcinols, also known as resorcinolic lipids, are phenolic lipids composed of long aliphatic chains and resorcinol-type phenolic rings.

Alkylresorcinols are relatively rare in nature, with the main known sources being wheat, rye, barley, triticale (cereal grasses), the fruit of Ginkgo biloba Bilobol, a mollusc and some species of bacteria.

DB-2073 is an antibiotic isolated from the broth culture of Pseudomonas sp. They are also the main constituents of the outer shell of the cyst of Azotobacter.

Alkylresorcinols are present in high amounts in the bran layer (e.g. pericarp, testa and aleurone layers) of wheat and rye (0.1-0.3 % of dry weight). 5-Alkylresorcinols can also be found in rice, though not in the edible parts of the rice plant.

They are only present in very low amounts in the endosperm (the part of cereal grain that is used to make white flour), which means that alkylresorcinols can be used as 'biomarkers' for people who eat foods containing wholegrain wheat and rye, rather than cereal products based on white flour.

Alkylresorcinols were thought to have anti-nutritive properties (e.g. decreasing growth of pigs and chickens fed rye), but this theory has been discredited, and a number of animal studies have demonstrated that they have no obvious negative effect on animals or humans.

Increasing evidence from human intervention trials suggests that they are the most promising biomarker of whole grain wheat and rye intake. Alkylresorcinol metabolites, 3,5-dihydroxybenzoic acid (DHBA) and 3,5-dihydroxyphenylpropionoic acid (DHPPA) were first identified in urine and can be quantified in urine and plasma, and may be an alternative, equivalent biomarker of whole grain wheat intake.

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